Flanking rudder



y 1941. H.-H. HORSTMAN 2,251,133

FLANKING RUDDER Filed Jan. 20, 1959 2 Sheets-Sheet 1 Patented July 29,1941 UNITE D: STATES. PATENT O FF ICE FLANKING RUDDER Herbert H.Horstman, Alton, Ill;

Application January 20, 1939, Serial N0. 251,905.

9 Claims.

The general object of this invention is to provide an improvement in theconstruction and operation of flanking rudders for tow boats which, inoperation, will enable the boat to be accurately steered while it isbeing backed, to be turned at a sharper angle than is possiblewith-flanking rudders now used and, generally, will enable the boat tobe turned in either direction while being backed, with facility,expedition and certainty, making it possible for the pilot to keep theboat under control at such times, even against extremely adverse winds,tides or currents.

The essential feature of the invention consists in having the flankingrudders off-set from the rudder posts in such-manner that in theirnormal, or parallel, position, or when turned at a slight angle, theywill be in the slip stream produced by the propeller; and when turned atan angle of forty-five degrees, they will align themselves to form asingle rudder double in length that of a single flanking rudder. Whenthe rudders are in a parallel position, they act to stabilize the courseof the boat owing to their location in the swift slip stream, whichoffers great resistance to lateral movement; when turned at a slightangle, but so as to be still positioned in the slip stream, they enablethe boat to be turned to a corresponding extent in either direction withrapidity and certainty; and when turned into alignment to form a singleflanking rudder, the slip stream will be diverted to one side and therudder will oiTer to the water a large area of resistance, inclined tothe median line of the boat at an angle of forty-five degrees, whichwill cause the stern of the boat to be turned to one side or the otherrapidly and positively, so that flanking movements of the boat may beeffected with certainty by the pilot, and the boat at the same time bekept under workable control, in practically all conditions of wind,tide, or current;

Where twin screw propellers are employed, it will be necessary toprovide a pair of my improved flanking rudders for each propeller. Insuch tow boats, the under side of the over-hanging stern portion isusually provided with two semi-circular, longitudinal recesses to affordworking spaces for the propellers, and the-tops of the flanking ruddersnecessarily move in a-plane slightly below these recesses, as otherwisethey could only be turned at a slight angle, and in the case of myrudders they would be prevented fromturning into alignment by contactwith the sides of the recesses. Such necessary positioning of therudders, however, leaves large-spaces, formed by said recesses, abovethe respective sets of flanking rudders, through which the water mayrush without encountering the resistance ofthe' rudders. To-overcomethis disadvantage, an important feature of the invention, in. connectionwith twin-screw propellertow'boats', consists in providing asupplemental rudder for each pair of flanking rudders, locatedintermediate and above the same, and mounted in the correspondingpropeller recess, these supplemental rudders being adapted to beoperated simultaneously with the main flanking rudders by the samesteering mechanism, and being of asize and shape as, whenturned at asufiicient angle, to substantially obstruct the passage of water throughthe respective recesses in which they are located and thereby tosupplement the action of the main flanking rudders in effecting'aflanking movement of the boat. a

The invention is illustrated in the accompanying drawings, in which Fig.1 is'a view in side elevation of the stern portionof a tow boat providedwith my improved flanking rudders Fig. 2 is aplan view of the same;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4- is a view similar to-Fi'g. 3, but showing the flanking ruddersturned into alignment to form a single rudder;

Fig. 5 is a bottom plan View of the parts shown in Fig. 1, the ruddersbeing shown by full lines in their normalposition, that is, paralleltothe propeller shaft and to each other, and by dotted lines in theposition they occupy when turned'to a'n'angle-of forty-five degrees toalign with each other;

Fig. 6 is a plan view of the stern portion of a' towboat having twinscrew propellers and showing my improvedflanking rudders appliedtheret'o;,and'

Fig. 7 is a cross-section on the line 1'-l of Fig. 6 showing thesupplemental; rudders I employ in. this type of tow boat.

Referring now to'the'drawings, the numeral I indicates the-hull of 'atow boat and 2 the stern portion thereof which, as usual, is'recessedtransversely 'andlongitudinally, as shown by Figs. 1 and. 3, to providean" over-hang 3, in the space beneath the underside of" which arelocated the main rudder 4, thepropeller 'o'and propeller-shaft 6 and;in. the present case, my improved flanking rudders l. Thereason-for'havingan overhanging stern is to permit therudders andpropellers to be mounted under the stern above the plane. of the bottomof'theboat; so thatthese parts will be protected from injury by comingin contact with the bottom of the stream, or river, in which the boat isoperating, or when the boat is passing over sand-bars. In order to mountmy improved flanking rudders beneath the over-hanging stern 3, Irotatably mount in the stern at a suitable distance apart a pair ofvertically-disposed rudder posts 8, which extend from-a point above thedeck- 9 through the stem to a point below the under side thereof;beingmounteddn bearings l0;

as usual. Mounted on the lower end of each rudder post is aninwardly-extending arm, or support, I I, secured on the inner end ofwhich is one of my flanking rudders 1, the rudders being se-' cured tothe supports in a manner to be substantially centered thereon, and saidsupports, in general, extending inward at right-angles to the rudderposts and securing the flanking rudders in parallel relation to eachother and, in their normal position, in parallel relation to the ruddershaft, as shown by Figs. 2 and 3. Each of the flanking rudders l isprovided at its front and rear end with a central recess l2, which areto permit the rudders to clear the propeller shaft when they are turnedinto alignment, as will presently appear.

For turning the flanking rudders to effect a flanking movement of theboat, I secure on the upper end of each rudder post above the deck alever-arm l3, Figs. 1 and 2, the outer ends of which are connected by anadjustable link It, centrally of which are secured the ends of steeringcables i5, which run over pulleys 16 located at opposite sides of thestern and thence to drums (not shown), whereby they may be manipulatedin the usual way to turn the flanking rudders simultaneously in onedirection or the other.

From an inspection of Figs. 2 and 5, it will be seen that the flankingrudders l in their normal position are within the area of draft of thepropeller, and accordingly will lie in the slip stream produced inoperation by the propeller. They thus materially aid in stabilizing theposition of the boat. But the principal advantage of my improvedflanking propellers is that they enable the pilot to effect a rapid andpositive flanking movement of the boat by converting the two ruddersinto a single rudder and thus presenting an inclined area of resistanceto the water substantially double the size of a single rudder. Toaccomplish this, the lever-arms l3 are turned by the cables IS in onedirection or the other through an arc of forty-five degrees and, asclearly shown by Fig. 5, this causes the outer end of one rudder to comein contact with and overlap the inner end of the other, at which pointthe rudders will align with each other to form a single rudder. It willbe apparent to those skilled in the art that a rudder of suchincreasedarea will effect a morerapid and positive turning of the sternthan would be possible with two flanking rudders operating individually,as is the common practice. Furthermore, with the two flanking ruddersaligned and positioned at an angle of forty-five degrees to the medianline of the boat, this single rudder will extend across the slip streamproduced by the propeller, causing it to be diverted to one side or theother, according to the inclination of the rudder, thus preventing theslip stream from passing under the boat and exerting a retarding action,and greatly adding to the rapidity with which the stern may be turned.

The main rudder 4 is positioned as usual at the stern of the boat, andoperated in the usual manner by steering cables H, or otherwise, and nofurther reference to this rudder is necessary.

It should be stated that the steering mechanism I have illustrated hasbeen adopted merely for simplicity of illustration, and modern methodsof operating the rudders would of course be employed in practice.

I wish it also understood that my invention is not to be limited inapplication to flanking rudders, as it is obvious that the principleinvolved would be equally applicable to the main rudders of boats,especially boats of the stern wheel type.

Referring to Figs. 6 and 'I, when my invention is applied to a tow boathaving twin screw propellers, a pair of my flanking rudders, l8 and [9,respectively, is positioned exactly in the manner previously describedforward of each propeller, 20 and 2|, respectively, all of thelever-arms [3 being connected by a common link 22, which is operated bythe steering cables I5 in the manner previously described, or by anyother preferred means. However, as stated, this type of boat is usuallyconstructed with two longitudinal, semi-circular recesses 23, 24,respectively, on the under side of the stern, providing working spacesfor the upper portion of the propellers, and as th tops of the flankingrudders must necessarily be located below these recesses in order thatthey may be turned through the desired angles, a relatively large spaceis left above the rudders when they are turned into alignment, throughwhich the water may rush without meeting the resistance of the rudders.To overcome this disadvantage, I mount in the stern, between each pairof rudder posts 25, 26, respectively, of the two sets of flankingrudders, an-

other rudder post 21, and on the lower end of each rudder post 21 Imount within the respectiv recesses 23, 24, a supplemental rudder 28,which is of the shape of the recess and of such length and size that,when turned to an angle of forty-five degrees, it will substantiallyobstruct the passage of water through its recess. Each rudder post 21 isprovided with a lever-arm 29 which is pivotally connected at its outerend to the link 22, so that all of the flanking rudders and supplementalrudders may be operated simultaneously. It will be seen that eachsupplemental rudder forms, in effect, an upward continuation in itsrecess of the flanking rudders, and when turned therewith to an angle offortyfive degrees, it will lie substantially in the plane of andimmediately over the flanking rudders and will therefore act tosupplement the action of the latter.

While I have described the flanking rudders as being turned intoalignment, I intend this word to have a wider range of meaning than itsstrict definition imports, in that it is not necessary that actualalignment, that is, contact with each other, of the rudders be effected,although such action is preferred. It will be apparent that the ruddersoperate on the principle of parallel rulers and are therefore alwaysparallel to each other. Thus both rudders may be turned to an angle offorty-five degrees and their parallel relation be maintained; and whilethe outer end of one would overlap the inner end of the other, theseoverlapping ends need not be in contact, but a considerable space couldbe left between them without in any manner detrimentally affecting theaction of the rudders as a single rudder.

I claim:

1. In combination with the propeller of a tow boat having anover-hanging stern, a pair of steering posts mounted in and projectingbelow the bottom of the stern forward of said propeller, a pair offlanking rudders mounted, respectively, on said steering posts andoff-set therefrom inwardly to lie normally in parallel relation in theslip stream produced in operation by the propeller, and means forsimultaneously turning said flanking rudders on their axes in eitherdirection.

2. In combination with the propeller of a tow boat having anover-hanging stern, a pair of steering posts mounted in and projectingbelow the bottom of the stern forward of said propeller,

a pair of flanking rudders mounted, respectively, on said steering postsand off-set therefrom inwardly to lie normally in parallel relation inthe slip stream produced in operation by propeller, and posiitoned atsuch distance apart that when both are turned in one direction or theother to an angle of forty-five degrees to the normal, said rudders willbe brought into alignment to form a single rudder, and means forsimultaneously operating said rudders.

3. In combination with the propeller of a tow boat having anover-hanging stern, a pair of steering posts mounted in and projectingbelow the bottom of the stern forward of said propeller, a pair offlanking rudders mounted, respectively, on said steering posts andoif-set therefrom inwardly to lie normally in parallel relation in theslip stream produced in operation by the propeller, and positioned atsuch distance apart that when both are turned in one direction or theother to an angle of forty-five degrees to the normal, said rudders willbe brought into alignment to form a single rudder, with the outer end ofone rudder overlapping the inner end of the other, and means forsimultaneously operating said rudders.

4. In combination with the propeller of a tow boat having anover-hanging stern, a pair of steering posts mounted in and projectingbelow the bottom of the stern forward of said propeller, an armprojecting inward at right-angles from the bottom of each steering post,a flanking rudder mounted intermediate its ends on the inner end of eachof said arms to lie normally in the slip stream produced in operation bythe propeller and in parallel relation with the companion rudder, saidrudders being positioned at such distance apart that when both areturned in one direction or the other to an angle of fortyfive degrees tothe normal they will be brought into alignment to form a single rudder,with the outer end of one rudder overlapping the inner end of the other,and. means for simultaneously operating said rudders.

5. In combination with the propeller of a tow boat having anover-hanging stern, a pair of steering posts mounted in and projectingbelow the bottom of the stern forward of said propeller, an armprojecting inward at right-angles from the bottom of each steering post,a flanking rudder mounted intermediate its ends and sides on the innerend of each of said arms to lie normally in the slip stream produced inoperation by the propeller and in parallel relation with the companionrudder, said rudders being positioned at such distance apart that whenboth are turned in one direction or the other to an angle of fortyflvedegrees to the normal they will be brought into alignment to form asingle rudder. with the outer end of one rudder over-lapping the innerend of the other, and means for simultaneously operating said rudders.

6. In combination with the propeller of a tow boat having an overhangingstern, a pair of steering posts mounted in and projecting below thebottom of the stern forward of the propeller, a shaft for the propellerextending centrally between said steering posts, a pair of flankingrudders mounted, respectively, on said steering posts and off-setinwardly therefrom toward said propeller shaft to lie normally inparallel relation therewith, each of said rudders being provided at eachend with a recess in alignment with said propeller shaft, said ruddersbeing positioned at such distance apart that when both are turned in onedirection or the other to an angle of fortyfive degrees to the normal,they will be brought into alignment to form a single rudder, with theouter end of one rudder overlapping the inner end of the other and therecesses in such ends encircling the propeller shaft, and means forsimultaneously operating said rudders.

7. In combination with a tow boat having twin screw propellers operatingbeneath an over-hanging stern provided with longitudinal, semi-circularrecesses affording working spaces, respectively, for the upper portionsof said propellers, a pair of steering posts mounted in and projectingbelow the bottom of the stern forward of each propeller, a pair offlanking rudders mounted, respectively, on the lower ends of each pairof said steering posts and ofi-set therefrom inwardly to lie normally inparallel relation directly forward of a propeller and within the area ofdraft thereof, the tops of said flanking rudders being located slightlybelow the open sides of said propeller recesses, a supplemental rudderfor each pair of flanking rudders pivotally mounted in a propellerrecess and operable simultaneously with the flanking rudders, the latterbeing positioned at such distance apart that when both are turned in onedirection or the other to an angle of fortyfive degrees to the normalthey will be brought into alignment to form a single rudder, and thesupplemental rudder being of a size and shape and so positioned thatwhen turned with the flanking rudders in either direction to an angle offorty-five degrees they will lie in the plane of and immediately overthe single rudder formed by said flanking rudders and will substantiallyobstruct the passage of water through the recess in which it is locatedand supplement the action of the flanking rudders, and means forsimultaneously turning both sets of flanking rudders and it;heirsupplemental rudders in the same direcion.

8. In combination with a tow boat having a propeller and the under sideof its stern providing a longitudinal space above the propeller, a pairof olT-set flanking rudders mounted directly forward of said propellerand in the area of draft thereof and adapted to be turned angularly intoalignment to form a single rudder, a supplemental rudder mounted in saidspace above said flanking rudders and movable in unison therewith toform, substantially, an upward aligning continuation in said space ofthe single rudder provided by turning said flanking rudders intoalignment, and means for simultaneously operating said flanking ruddersand the supplemental rudder.

9. In combination with the propeller of a boat, a pair of steering postsmounted in and below the bottom of the stern forward of said propeller,a pair of flanking rudders mounted, respectively, on said steering postsand ofi-set therefrom inwardly to lie normally in parallel relation inthe slipstream produced in operation by the propeller, and means forsimultaneously turning said tflanking rudders on their axes in eitherdirecion.

HERBERT H. HORSTMAN.

